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The visible dashed area where users drop files. It accepts the file input in the UI but typically does not persist the file anywhere by itself; storage must be implemented separately on the backend
A client-side preview of the selected image generated immediately in the browser. This preview is created before the file ever reaches a server and can be faked in demos, so it’s not proof of successful upload
Displays upload progress to the user as feedback while files are being sent. It is purely cosmetic unless wired to a real upload endpoint that reports actual transfer progress
Represents the actual storage destination where files must land (for example, an object store). Most widgets show this conceptually but leave the real storage implementation up to you
Server-side validation that checks file type, size, and other security rules to stop malicious uploads. Always enforce these checks on the backend rather than trusting client-side controls